Graal + AWS Java Lambda + Golang

build.sh

# Scripts to build
go build -buildmode=c-shared -o libHello.so src/main/go/lambda.go

$GRAALVM_HOME/bin/native-image Test -cp "target/graalvm-java-go-awslambda-1.0-SNAPSHOT.jar" \
	-H:+JNI \
	-H:+ReflectionEnabled \
	-H:+ReportUnsupportedElementsAtRuntime \
	-Djava.library.path=$(pwd) \
	--no-server

lambda.go

package main

//#cgo CFLAGS: -I/usr/lib/jvm/java-8-openjdk-amd64/include
//#cgo CFLAGS: -I/usr/lib/jvm/java-8-openjdk-amd64/include/linux
//#include <jni.h>
import "C"
import (
	"net"
	"fmt"
	"github.com/aws/aws-lambda-go/lambda"
	"encoding/json"
)

//export Java_Test_start
func Java_Test_start(env *C.JNIEnv, clazz C.jclass) {
	fmt.Println("Hello from Go")
	StartServer()
}

const (
	servAddr = "localhost:6789"
)

func communicateJava(input interface{}) (interface{}, error) {
	tcpAddr, err := net.ResolveTCPAddr("tcp", servAddr)
	if err != nil {
		return nil, err
	}

	conn, err := net.DialTCP("tcp", nil, tcpAddr)
	if err != nil {
		return nil, err
	}
	defer conn.Close()

	inBytes, err := json.Marshal(input)
	if err != nil {
		return nil, err
	}

	// Write it to TCP socket
	_, err = conn.Write(inBytes)
	if err != nil {
		return nil, err
	}

	// Signal we won't be writing anything soon
	err = conn.CloseWrite()
	if err != nil {
		return nil, err
	}

	// Not ideal at all
	reply := make([]byte, 3*1024*1024)

	n, err := conn.Read(reply)
	if err != nil {
		return nil, err
	}

	var resp interface{}
	err = json.Unmarshal(reply[0:n], &resp)

	return resp, err
}

func StartServer() {
	lambda.Start(communicateJava)
}

func main() {
	//StartServer()
	/*
		out, err := communicateJava([]byte("osman"))
		if err != nil {
			log.Fatal(err)
		}
		log.Println(string(out))
	*/
}

Test.java

import org.json.JSONObject;
import org.json.JSONTokener;

import java.io.BufferedReader;
import java.io.InputStreamReader;
import java.net.ServerSocket;
import java.net.Socket;

public class Test {

    public static void aq() {
        String s = "{\"a\":123}";
        JSONTokener tokener = new JSONTokener(s);
        JSONObject root = new JSONObject(tokener);
        System.out.println(root);

        int a = root.getInt("a");
        System.out.println(a);
    }

    public static native void start();

    public static void main(String[] args) throws Exception {
        System.out.println("Starting");
        System.loadLibrary("Hello");
        System.out.println("loaded lib");
        new Thread(() -> {
            System.out.println("starting");
            start();
        }).start();

        System.out.println("Sleeping 3sec");
        Thread.sleep(3000);
        System.out.println("Wow, slept 3 sec");

        ServerSocket serverSocket = new ServerSocket(6789);
        while (true) {
            System.out.println("listening");
            Socket socket = serverSocket.accept();
            System.out.println("accept");
            BufferedReader in =
                    new BufferedReader(new InputStreamReader(socket.getInputStream()));

            String read = in.readLine();

            System.out.println("java read: " + read);
            String reply = "from java reply: " + read;

            socket.getOutputStream().write(reply.getBytes());
            socket.close();
        }
    }
}